This report indicates that if an anomalously arising left main coronary artery (LMCA) courses anterior (Group A) to the right ventricular outflow tract, behind the right ventricular outflow tract (infracristal) Group C, or dorsal (Group D) to the ascending aorta, symptoms of cardiac dysfunction or myocardial ischemia do not result. In contrast, if the anomalously arising LMCA courses between (Group B) the pulmonary trunk and ascending aorta, symptoms of myocardial ischemia usually occur and that death is a frequent consequence.